A Very Unusual Tube Amp Problem......and Repair

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  • เผยแพร่เมื่อ 29 เม.ย. 2016
  • While working on a Davis 106 P.A. amp, I encountered a serious problem which is quite uncommon in guitar amps. In addition, the cause of the problem.....and its resolution.....were equally unusual. It's a fairly short video, and I think/hope you will enjoy the progressive diagnosis and repair. See if you can predict the cause of the problem.
    Please subscribe if you have not already done so. Rusty and I sincerely appreciate your time and interest.
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ความคิดเห็น • 540

  • @2right4words
    @2right4words 7 ปีที่แล้ว +35

    I love the Precision and Clarity of your videos!

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว +1

      Thanks, 2R :)

    • @randolphpatterson5061
      @randolphpatterson5061 7 ปีที่แล้ว +1

      I love the clarity of his videos, too, but I prefer the Jazz to the Precision..

  • @jimlabos
    @jimlabos 2 ปีที่แล้ว

    Thanks for taking us on this journey with you. So much to learn from you.

    • @UncleDoug
      @UncleDoug  2 ปีที่แล้ว +1

      Thanks, Jim, for joining us and for posting a nice comment.

  • @audiotechlabs4650
    @audiotechlabs4650 8 ปีที่แล้ว +2

    Wow Back to Back gems! These videos give me such encouragement. Thankz

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Audio Tech Labs You're welcome, ATL :)

  • @jasonbrindamour903
    @jasonbrindamour903 7 ปีที่แล้ว

    Cheers to Rusty and yourself sir...A big thanks for not being afraid to share this information with us in a video format. I greatly appreciate your knowledge.

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      You're welcome, Jason :)

  • @ionizerusa
    @ionizerusa 4 ปีที่แล้ว

    Dear Uncle Doug, you bring back a multiple dose of memories for me. Many thanks!

    • @UncleDoug
      @UncleDoug  4 ปีที่แล้ว

      I hope they are pleasant ones, Tim. You're welcome.

  • @Finom1
    @Finom1 8 ปีที่แล้ว

    This is the best way to spend a Saturday watch Uncle Doug & Rusty work their magic. Thank you for teaching us!!!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Finom1 You're welcome, F1.....glad you enjoyed the video :)

  • @kevinbeckenham3872
    @kevinbeckenham3872 8 ปีที่แล้ว +1

    Thanks for a great documentary on motor boating problem that happen from to time on valve amplifier. Keep up the good works you do amplifiers.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      You're welcome, Kevin. Thanks for your nice comments. We will do our best :)

  • @edwardhannigan6324
    @edwardhannigan6324 3 ปีที่แล้ว +1

    Hi Doug, still trawling through your videos in my quest for electronic knowledge. Unusual noise and great fix. It's amazing all the things that can go wrong in an amp circuit. I know this is one of your older videos, but enlightening non the less. Good to see Rusty' enthusiasm brimming over. Look forward to anything new in the pipeline..Thanks again for all this knowledge..Ed..U.K..😀

    • @UncleDoug
      @UncleDoug  3 ปีที่แล้ว

      Thanks, Ed. It's always good to hear from you.

  • @supermist100
    @supermist100 8 ปีที่แล้ว

    Nice to see Rusty is still with us! Thanks 4 your videos!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Haroslav Drastic Like death and taxes, Haroslav, Rusty and I are here to stay :)

  • @vhm14u2c
    @vhm14u2c 5 ปีที่แล้ว

    Amazing TS work on finding the issue with the open winding on the output xformer. Thanks for sharing!

    • @UncleDoug
      @UncleDoug  5 ปีที่แล้ว +1

      Thanks, Vince :)

  • @davida1hiwaaynet
    @davida1hiwaaynet 7 ปีที่แล้ว

    Excellent repair. Never give up on anything - locating and repairing the transformer problem is always so satisfying.

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      Thanks, David :)

  • @daveb9370
    @daveb9370 8 ปีที่แล้ว +2

    Hey Uncle Doug, great video and, once again, glad Rusty solved the mystery! Very educational, I learn alot from watching you guys work. I hope Rusty isn't pushing you too hard. My Husky Igloo pushes me hard sometimes, but he says it's for my own good, and I guess he's right. Have a great day and keep the great videos coming!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Dave Bogusky Thanks, Dave, and regards to Igloo :)

  • @JoelzombieThomas
    @JoelzombieThomas 6 ปีที่แล้ว

    This is one of the most brilliant repairs I've seen you do. I've mentioned it before, but that emphatic tapping on amplifier components you do has brought so much joy to my life. My new wife and I laugh a lot when doing the Uncle Doug Tap. You should patent it. We are big fans and hope to meet you someday.

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      Thanks so much, Joel. It took many years to perfect "the tap" and I'm glad someone out there appreciates it :)

  • @harrisonhein1287
    @harrisonhein1287 8 ปีที่แล้ว +1

    So happy to see you and Rusty making videos again. You've helped me heaps with learning and fixing amps

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Harrison Hein That's good news, Harrison.....keep up the good work. Old amps need love too :)

    • @harrisonhein1287
      @harrisonhein1287 8 ปีที่แล้ว +1

      Will do

  • @kardRatzinger
    @kardRatzinger 8 ปีที่แล้ว +10

    Usually I hear the term "motorboating" used to describe something completely different than an amp failure :)
    Congratulations on the repair.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +2

      +kardRatzinger Thanks, Kard. I understand there are several other meanings for the term, but I think you can see why it's particularly appropriate in this case :)

    • @fortj3
      @fortj3 5 ปีที่แล้ว +1

      Absolutely. Usually when I hear motorboating of an amp, it reminds me of a thumper.
      Sounds a lot like my Yamaha SR400 idling.

  • @Zone1242
    @Zone1242 8 ปีที่แล้ว +1

    Nice one Doug. I've never been lucky enough to find the broken end of the winding - usually buried down inside somewhere. Thanks for another great video.
    Cheers, John

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +1

      You're welcome, John. I figure there is nothing to lose, so I root around looking for the broken lead and am sometimes able to find it.....but not always :)

  • @waynekozak1462
    @waynekozak1462 6 ปีที่แล้ว +3

    Hey Uncle Doug!
    Great video
    you are a superb diagnostician
    Thanx
    I am glad to see that Rusty has everything under control, as always !! LOL

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      You're welcome, Wayne. We appreciate it :)

  • @marviosantos
    @marviosantos 8 ปีที่แล้ว

    HA! I actually "guessed" the problem before you got to the conclusion, and I only even mention it because this is a credit to you sir, for teaching me all I know about tube amps! Thanks for another great video!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Marvio Botticelli You're welcome, Marvio. It looks like the student has progressed beyond the teacher :) Rusty and I are glad the videos were helpful. Thanks for watching.

  • @budandbean1
    @budandbean1 8 ปีที่แล้ว

    Wow, that's very interesting, congrats for finding the fault Uncle Doug. I actually didn't know that you could find and much less correct a break in a transformer winding, I really learned several things today. Thank you Uncle Doug...

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Buddy Martin You're welcome, Buddy. The trick is to find the other end of the broken lead. Most of the time, I can, and if so then it's generally fairly easy (not on the eyes) to mend the break. Once repaired, the OPT is generally as good as new.

  • @leftyfusion88
    @leftyfusion88 8 ปีที่แล้ว

    Great videos for someone like me who is trying to absorb how this stuff all works. Thanks again.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      You're welcome, Lefty.

  • @vminator
    @vminator 5 ปีที่แล้ว +1

    You sir have been a huge source of information for us all. Because of watching all your videos over and over again, I am now on my third scratch built tube amplifier! I love the sound so much I sold all my other amps! I hope your shop assistants and yourself are doing great. Keep the videos coming!!

    • @UncleDoug
      @UncleDoug  5 ปีที่แล้ว

      That's great to hear, Miguel. Congratulations on your scratch-building success. We will :)

    • @vminator
      @vminator 5 ปีที่แล้ว

      @@UncleDoug Had a question for you, If I'm using a PT with 120mA HV secondary. Do I need to use a filter choke thats rated for 120mA? or does the filter choke only need to be rated for the current your actually drawing from that secondary? I have a 100mA filter choke I want to use but the PT secondary is rated at 120mA. Would it blow the filter choke?

  • @ix-Xafra
    @ix-Xafra หลายเดือนก่อน

    This gem came up in my Ewetube feed at 4am.
    Love your work, Doug
    Regards from Vinny in Brisbane

    • @UncleDoug
      @UncleDoug  หลายเดือนก่อน +1

      Thank heavens you were up to watch it, Vinny. Thanks for the nice comments :)

  • @CC-te5zf
    @CC-te5zf 5 ปีที่แล้ว

    Wonderful demo of preservation, v/s t/s by component replacement. This is great!

    • @UncleDoug
      @UncleDoug  5 ปีที่แล้ว

      Thanks, Chad :)

  • @breth8159
    @breth8159 8 ปีที่แล้ว

    Rusty the Wonder Dog awesome.
    the little mouse that chewed on your Transformer not so is awesome
    I find in vintage well-lit magnification in close-up inspection saves me a lot of call backs
    thanks another great video

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Bret H I agree with your analysis, Bret. Thanks for watching and commenting :)

  • @Barnekkid
    @Barnekkid 8 ปีที่แล้ว

    Another good one from Uncle Doug and his enthusiastic pet. Just wanted to say thank you for the tip about the analog meter. I have a Simpson 260 also, but I largely kept it for posterity. Now I have a good reason to use it, maybe.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +1

      +Barnekkid Analog meters can perform tasks that digital meters cannot. They are both very valuable and useful tools. By all means, dust it off and begin using it, BK. You will wonder how you ever did without it :)

  • @StonyRC
    @StonyRC 8 ปีที่แล้ว

    Hi Uncle Doug (and Rusty) - That was a Masterful diagnostic procedure and your repair was positively surgical - a job equal to any Vascular Surgeon!. Thoroughly entertaining and (as always) extremely interesting. Please keep 'em coming.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +StonyRC Thanks, Stony. Now, if I could only get PAID like a vascular surgeon, Rusty's (and my) menu would definitely improve :)

  • @saturn5tony
    @saturn5tony 8 ปีที่แล้ว +2

    Awesome repair on this cool PA Doug. Seems Rusty's language skills are improving as well. Looking forward to your next vid, thanks4sharing.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +saturn5tony You're welcome, Tony....glad you liked it.

  • @RossDuClair
    @RossDuClair 7 ปีที่แล้ว

    Doug: Nicely done. Great piece of deductive reasoning and trouble shooting. This "eaten" transformer would be rare to most people, but with more than three decades of repairing broadcast transmitters and other remote location electronics, I have replaced many chewed on components, removed at least three snakes from blower inputs and scrubbed more than my share of rodent urine from circuit boards.

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว +1

      Thanks, Ross. One of my favorite "de-animalizations" was the removal of a putrid rat's nest, constructed mainly of tin foil, from the chassis of a really nice early tweed Gretsch amp......I shudder to think about the "light show" that might have occurred if I had simply plugged it in, as-is.

  • @alanpassat6759
    @alanpassat6759 8 ปีที่แล้ว

    Jack Darr mentioned this in his book, and I had always wondered what it sounded like. Thanks for posting!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Paul Passat You're welcome, Paul. I have heard it before, when working on radios, but have never encountered the problem with a guitar or PA amp. It generally "putts" at a faster rate, but the sound is unmistakable.

  • @djvycious
    @djvycious 8 ปีที่แล้ว

    Uncle Doug! Glad to have you back! Would love to see a video about some vintage rock amps and getting the perfect overdrive sound.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Cameron Walker Thanks, Cameron. It's good to be back. Hopefully, some vintage rock amps will show up for sale or repair. If they do, I will definitely feature them in videos.....so stay tuned :)

  • @jwl9286
    @jwl9286 7 ปีที่แล้ว

    wonderfully done. loved it, thanks

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      You're welcome. Thanks for the nice comments.

  • @toxicgraphix
    @toxicgraphix 8 ปีที่แล้ว

    I love your videos! Thank you so much for passing down your knowledge to us all... and future generations. I noticed this video has one thumbs down, somebody must have hit the down button by mistake... I can't believe anyone would dislike any of your videos.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +toxicgraphix You're welcome, TG, and thanks for your very nice comments. Rusty and I really appreciate it :)

  • @fredbloggs4829
    @fredbloggs4829 4 ปีที่แล้ว

    Great video. Loved the commentary, especially the part about grabbing a beer and pulling up a comfortable chair.

    • @UncleDoug
      @UncleDoug  4 ปีที่แล้ว

      It's always a good way to begin any conversation :)

  • @klokibril
    @klokibril 8 ปีที่แล้ว

    Great explanation and nice repair job. Thanks for the upload!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +1

      +Joop S You're welcome, JS :)

  • @aaronjohnmaughan
    @aaronjohnmaughan 4 ปีที่แล้ว

    Some fine troubleshooting here. Well executed repair, too.

    • @UncleDoug
      @UncleDoug  4 ปีที่แล้ว

      Thanks, Aaron.

  • @florascent9ts
    @florascent9ts 3 ปีที่แล้ว

    love to hear troubleshooting thought processes!

    • @UncleDoug
      @UncleDoug  3 ปีที่แล้ว

      It's our pleasure to share them with you, CC.

  • @kendavis8046
    @kendavis8046 8 ปีที่แล้ว +1

    My dog Tater says Rusty is one cool dog!
    These are really interesting videos, and thanks so much for posting.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Ken Davis You're welcome, Ken, and best regards to Tater :)

  • @49VinCom
    @49VinCom 6 หลายเดือนก่อน

    Great troubleshooting. Thanks for sharing.

    • @UncleDoug
      @UncleDoug  6 หลายเดือนก่อน

      Thanks. Glad you enjoyed it :)

  • @kennethjanczak4900
    @kennethjanczak4900 6 ปีที่แล้ว +1

    Thanks for another good video, really like the way u explain things
    Keep the videos comming😊😊😊

  • @deluxetone
    @deluxetone 7 ปีที่แล้ว

    Thanks for another fantastic and informative video. Excellent content and very entertaining
    .

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      You're welcome, DT.....glad you liked it :)

  • @bluesingmusic3443
    @bluesingmusic3443 3 ปีที่แล้ว

    Good find Uncle Doug. I love the old Simpson 260, that one looks just like the ones I used in the Navy. (Back when I still remembered most of the stuff they taught me during my year & a half of Aviation Electricians training. We went in depth on vacuum tubes, etc. Unfortunately I rarely used any of that knowledge in the decades following. I'd even forgotten the resistor "code" about "Bad boys....etc". Perhaps that's why I enjoy these videos so much, I'm forever thinking,"wow, now I remember that.) Youth is indeed wasted on the young.(at least in my case.)

    • @UncleDoug
      @UncleDoug  3 ปีที่แล้ว +1

      Thanks, BiG........glad you enjoyed it. We do tend to lose that which we cease to use.

  • @jackallen6261
    @jackallen6261 5 ปีที่แล้ว

    I LOVE these old Davis amps, so cool. I have a pair of Infinity speakers to "re-foam" (replace the foam surrounds on the cones) tomorrow, baby steps, lol. Maybe one day I can work my way up to re-coning a speaker...maybe. As always very informative and helpful video! Thanks

    • @UncleDoug
      @UncleDoug  5 ปีที่แล้ว

      You're welcome, Jack. Good luck with your project.

  • @aaronjohnson8211
    @aaronjohnson8211 7 ปีที่แล้ว +1

    You're truly the king of amp repair

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว +2

      If it weren't for Rusty's guidance, I would just be an old hack :)

  • @nikoladivic2786
    @nikoladivic2786 7 ปีที่แล้ว

    Very nice explanations like ever.Thank you !!!

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      You're welcome, Nik :)

  • @michaelpukmel9175
    @michaelpukmel9175 7 ปีที่แล้ว

    Oh my gosh LOOK at that transformer! That's a keeper, have to frame it! :) You're a master, Doug.

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      Thanks, Michael.

  • @zbdd8
    @zbdd8 7 ปีที่แล้ว

    So helpful and detailed. Thank you!

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      You're welcome, ZB :)

  • @RandySchartiger
    @RandySchartiger 8 ปีที่แล้ว +2

    Great video Doug! And a very unusual problem. Rusty was smart to leave it to you, tell Rusty Q-ball says hey! :)

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Randy Schartiger Thanks, Randy.....glad you liked it. Regards to Q-Ball :)

  • @johncunningham5435
    @johncunningham5435 8 ปีที่แล้ว

    I have serviced countless amps over at least 35 years or more and never run into this type of problem. It has always been a bad capacitor in most cases that caused the motor boating, but in the open winding of one side of the tap the sound was distinctively different. Your analyzes of half the active tap does suggest the capacitor is charging and discharging creating that most unusual sound, and after careful thought I have come to the same conclusion you have, and agree with your findings. "Well Done"

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +John Cunningham Thanks, John. I've never seen it before in a guitar amp, and it's good to know that I'm not alone. It now seems to perform and behave quite well, so the problem appears to be fixed.

  • @repairfreak
    @repairfreak 4 ปีที่แล้ว

    Thanks for the video Uncle Doug, give Rusty a hug and a treat from me too. Best wishes always.

    • @UncleDoug
      @UncleDoug  4 ปีที่แล้ว

      You're welcome, Mike. Sadly, Rusty passed away several years ago, but I'm sure he would have appreciated your kindness.

    • @repairfreak
      @repairfreak 4 ปีที่แล้ว

      Uncle Doug
      Im sorry to hear this Uncle Doug, he looked like such a nice boy. I love our dogs like children, sometimes I think even more because my dogs don’t disrespect me, lol. All the wonderful creatures need is love, food, water and a warm bed and they are totally content and give back love in such great magnitude.
      Keep up the great work with your very helpful videos, you have furthered my knowledge considerably, and for this I thank you sir, God bless 🙂❤️

  • @vonzigle
    @vonzigle 8 ปีที่แล้ว +1

    Nicely done! 👍

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      Thanks, VonZ :)

  • @cawfeedawg
    @cawfeedawg 8 ปีที่แล้ว

    Missed your videos.. welcome back Doug.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +1

      +Cawfee Dawg Thanks, CD. It's good to be back :)

  • @T25de
    @T25de 4 ปีที่แล้ว +1

    Interesting repair

  • @zanebullard8665
    @zanebullard8665 2 ปีที่แล้ว +1

    Hey there Doug! I'm new to your channel, and I love your vids! I'm a guitar tech looking to get into amp repair and your videos have been a great insight into it!
    Cheers!

    • @UncleDoug
      @UncleDoug  2 ปีที่แล้ว +2

      Greetings, Zane. That's great to hear. Best of luck with your new career :)

  • @Barefeet200
    @Barefeet200 8 ปีที่แล้ว

    Wow a video to go with my morning tea, and then one to serve as a nightcap ! Great feeling when you can save a transformer, nicely done Uncle Doug.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Barefeet200 Thanks, BF :)

  • @charliebrowncbiii
    @charliebrowncbiii 8 ปีที่แล้ว

    I've only watched a handfull of your videos and i got to say I'm hooked....keep em coming uncle doug and say hi to rusty for me!!!!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +charlie brown We will, Charlie......and Rusty says "hi" to you all.

  • @SiliconSet
    @SiliconSet 8 ปีที่แล้ว

    Great video, many thanks! Rusty thinks you covered this so well he had no need to contribute.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +SiliconSet Thanks, SS. I guess he always thinks that way :)

  • @cassvirgillo3395
    @cassvirgillo3395 8 ปีที่แล้ว +5

    Hey Uncle Doug & Rusty, Good to see you boy's up to your old trick's. Good diagnosis and repair, you are good. I am learning so much from your amp video's I almost feel qualified, not. I hope all is well with you and your's. 80's comin' here in Oregon and looking green with the leave's coming on. Take care, C.

    • @cassvirgillo3395
      @cassvirgillo3395 8 ปีที่แล้ว

      ***** Hey Sceaming deal, Yes, very nice . I'm just outside Willamina, so not to far from Lincoln City. I've seen some nice day's at LC. Will take the winter's for the summer's. Thanks for commenting. Be good, C.

    • @BrianOfAteionas
      @BrianOfAteionas 8 ปีที่แล้ว

      +Cass Virgillo Hey fellow Oregonian! The weather was perfect here in Portland today. Good day for beers, music, and top it all of with a super cool Uncle Doug video. What could be better?

    • @cassvirgillo3395
      @cassvirgillo3395 8 ปีที่แล้ว

      BrianOfAteionas Hey Brian, I couldn't agree more. Happy 1st. Uncle Doug is my favorite channel. I'm getting part's together to build a Fender 5F1 Champ as seen in his 2 part video series. Take care, C.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +1

      +Cass Virgillo It looks like you Northwesterner's are having a nice chat. Thanks for all the nice comments.....Rusty and I really appreciate hearing from you all.

    • @cassvirgillo3395
      @cassvirgillo3395 8 ปีที่แล้ว

      Uncle Doug Hi Uncle Doug, I've never had so many reply's to one comment. Be good, C.

  • @guitardavidc
    @guitardavidc 6 ปีที่แล้ว

    Uncle Doug, definitely enjoy your videos. Rusty Too!! 🎸

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      That's good to hear, GM :)

  • @ThomasACarlos
    @ThomasACarlos ปีที่แล้ว

    Permatex High-Temp Silicone Gasket, who knew? I learned something today. Thanks Uncle Doug.

    • @UncleDoug
      @UncleDoug  ปีที่แล้ว

      You're welcome, Thomas.

  • @TheGuitologist
    @TheGuitologist 8 ปีที่แล้ว

    Nice job on a successful repair. I really like the look of these amps. Unusual and cool. I guess they'll join Alamo Amps as the only vintage amp companies I'm aware of from Texas.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +The Guitologist Thanks, Brad. Yes, they are very well-made, attractive, compact, and functional. I would say they are one of the best candidates I can think of for guitar conversion.....and, as you said, one of only two brands I can think of from Texas :)

  • @ziggfreud9820
    @ziggfreud9820 8 ปีที่แล้ว

    excellent video. really enjoy your videos.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +John Miner Thanks, John. Rusty and I appreciate the nice comments.

  • @krang07
    @krang07 8 ปีที่แล้ว

    Enjoy all your videos Uncle D. Keep um comin`! Cheers!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +August Lyons Thanks, August....we will :)

  • @dwightbehm4747
    @dwightbehm4747 4 ปีที่แล้ว

    As usual another fine vidio Uncle Doug
    I like what Ypu did for the output transformer for the amp very logicle choice of methods I was a service technician at a chevy dealership and used high temp silecone
    Sealers and twopart
    Fast or slow hardening epoxies
    For some repairs on things I think I would do the same as you. Wish I had a shop like yours live long and
    Prosper. Dwight from Detroit,Mi.

    • @UncleDoug
      @UncleDoug  4 ปีที่แล้ว

      Thanks so much, Dwight. Likewise :)

  • @johnzook7533
    @johnzook7533 8 ปีที่แล้ว

    Oh man, do I wish I still had that old Sunn Sentura II. After doing a bit of work on it ...tone stack and adding a bypass cap to brighten it up after a bit it developed a ticking noise in the audio. As I say if I still had that amp, it would be interesting to see just hwat caused it. The amp worked but it had that tick motor boating instead of a lower frequency thump.
    As always another fine video and Rusty as usual makes a great producer.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      Thanks, John. Rusty and I appreciate the kind words :)

  • @Pwaak
    @Pwaak 5 ปีที่แล้ว

    Great video and a very good repair! Got a good laugh at video beginning, sounded like someone knocking on the door! Hi to Rusty!

    • @UncleDoug
      @UncleDoug  5 ปีที่แล้ว

      Thanks, Tony.

  • @timothybedwards5440
    @timothybedwards5440 5 ปีที่แล้ว

    Awesome repair

    • @UncleDoug
      @UncleDoug  5 ปีที่แล้ว

      Thanks, Tim :)

  • @is1amizationbyimmigration262
    @is1amizationbyimmigration262 8 ปีที่แล้ว

    my first guess, was that a capacitor was installed backwards.
    Your videos are always enjoyable another 10 out of 10

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Is1amization by Immigration Thanks, I by I. I too initially suspected a filter cap as the likely culprit.

  • @PLINKER
    @PLINKER 3 ปีที่แล้ว

    I would not know a wizard with more knowledge than you Uncle Doug!

    • @UncleDoug
      @UncleDoug  3 ปีที่แล้ว

      There are people out there who have forgotten more than I know, Tom.......but thanks !!

  • @aperioguitar
    @aperioguitar 8 ปีที่แล้ว

    Awesome Uncle Doug!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +aperioguitar Thanks, AG :)

  • @redfishbum
    @redfishbum 8 ปีที่แล้ว

    Simply AMAZING!!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +redfishbum Thanks, Bart :)

  • @donaldfilbert4832
    @donaldfilbert4832 8 ปีที่แล้ว

    Great Video Uncle Doug !! I was surprised to see how small that wire was on the primary / High voltage side of that output transformer. Nice save !!

    • @tubical71
      @tubical71 8 ปีที่แล้ว +1

      +Donald Filbert The diameter of a tranny coil wire only depends on the current flowing through at first glances. As being this one the wire of the primary coil the current through it is rather small.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +2

      +TubiCal Good answer, TC. Thanks.

  • @supyrow
    @supyrow 8 ปีที่แล้ว +2

    Hey Uncle Doug, Hey Rusty! Great Video, Love it!
    73!

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +su pyrow Thanks, SP :)

    • @supyrow
      @supyrow 8 ปีที่แล้ว +1

      You got it good buddy!
      73!

  • @andrewdarnley4608
    @andrewdarnley4608 8 ปีที่แล้ว

    Another great demo of fault finding and selection of suitable repair materials.
    After watching Rusty's reaction over a number of videos i don't think he's camera shy. I reckon he's waiting for a proper remuneration deal before he'll stay in front of the camera. Maybe get your people to talk to his people ?

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +1

      Thanks, Andrew. Rusty is a tough negotiator, but his agent is even worse.....we're still working on his new contract :)

  • @benmorris4589
    @benmorris4589 8 ปีที่แล้ว

    Great, as usual. It struck an immediate chord with me, as I have a transistor P.A. amp, which developed the same problem. One minute it was working, with my Fender going through it - the next thing, all hell broke loose, and at a high rate of level! I'm sure you said that the problem on yours was caps, in the power supply? Maybe I'll climb in there and see what I can do, otherwise I'll have to spend some (a lot of) pennies! Keep 'em coming! Ben.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Ben Morris Thanks, Ben. In my case, it was caused by an open primary winding in the output transformer, but filter caps are a more common cause of the problem.....usually accompanied by a hum. Good luck with the repair.

    • @benmorris4589
      @benmorris4589 8 ปีที่แล้ว +1

      Thanks, Doug. (When I get round to it)!

  • @GregsGarage
    @GregsGarage 8 ปีที่แล้ว +3

    I always enjoy your vids UD and Rusty.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Greg's Garage Thanks, Greg :)

    • @ThaUltimateDragon
      @ThaUltimateDragon 8 ปีที่แล้ว +1

      +Greg's Garage
      Hey Greg! Cool to see you here.

    • @GregsGarage
      @GregsGarage 8 ปีที่แล้ว +1

      I love this channel... Sometimes you'll see me post as SkyScraper Guitars too!!! UD &R rock.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +1

      Thanks, Greg. Rusty and I have come to really like and appreciate our viewers....like you. What a great extended family we all belong to :)

  • @VegasCyclingFreak
    @VegasCyclingFreak 7 ปีที่แล้ว

    Very interesting problem, never seen that one before. Nice fix on that OT

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      Thanks, VC :)

  • @otteronbass
    @otteronbass 8 ปีที่แล้ว

    thanks for another great video

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +otteronbass You're welcome, Otter.

  • @RickGreenPhoto
    @RickGreenPhoto 4 ปีที่แล้ว +1

    great video!

  • @troynorris7666
    @troynorris7666 8 ปีที่แล้ว

    Uncle Doug, I appreciate your videos and technical expertise. I had a volume fade problem with my Marshall JCM 2000 DSL 50 a few months ago. I am a guitarist,not an amp repair technician so I took my amp to a man referred to me by a friend. After spending 282.00 I brought the amp home and had the same problem. Volume fade and then after a few minutes it may or may not work "correctly". After searching and reading many forums I came across someone who had the exact same problems I was having. I ordered a new $2.95 bridge rectifier and installed it myself. Then I learned that after making such a repair it is necessary to check the bias voltage. I nearly burned up my power tubes. They looked like light bulbs. Max voltage should be 45 ma and mine were around 96ma. A readjustment and my amp has not sounded so good in years. Now if I could only figure out a way to add a separate EQ to the amp and lower the high gain white noise it would truly be what an amp should be. Being able to EQ the clean channel and the dirty channel separately is no brainer and I have often wondered why Marshall didn't include this in the original design. Thanks again for your videos sir .

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      You're welcome, Troy, and congratulations on a successful repair of your amp. That was a close call on the plate current. I shudder to think what your plate dissipation was at 96mA for each output tube. To reduce your gain and mellow things out a little, you might try experimenting by substituting lower gain duo-triodes (12AT7, 12AU7, 12AY7, etc.) for one of the 12AX7's in your pre-amp.

    • @troynorris7666
      @troynorris7666 8 ปีที่แล้ว

      Ahhh, I was under the impression that my power tubes were burning so hot due to the failing Bridge rectifier that was in the amp originally. After installing a new one that is beefed-up according to the specifications I assumed that was the reason why the voltage changed on my power tubes. 45 milliamps is maximum for my amplifier readjusting the bias after replacing the bridge rectifier has put the amplifier back in correct operating condition. I am an automotive technician by trade so I do understand alternating current and direct current. I am slowly learning the current flow in a guitar amplifier and why components do what they do.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      Tubes overheat when the plate voltage and plate current within them is too high. This would not be the result of a failing rectifier or a new rectifier, but because the bias of the tubes is set incorrectly. Biasing involves more than simply adjusting the plate current. You should watch my video on biasing of double-ended amplifiers to see and understand the full process.

  • @JesusIsLordofMybeing
    @JesusIsLordofMybeing 7 ปีที่แล้ว

    Nice save Uncle Doug!!!

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      Thanks, JT :)

  • @stevenwilliamdewitt
    @stevenwilliamdewitt 8 ปีที่แล้ว

    impressive! You are truly the Man

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Steve Dewitt Thanks, Steve :)

  • @benmorris4589
    @benmorris4589 8 ปีที่แล้ว

    Well, of course, apart from the broken winding! It took me back to the sixties, when we used to use radios as guitar amps, connecting up to the cap of the first valve (detector?).

  • @nor4277
    @nor4277 5 ปีที่แล้ว

    Thanks for the transformer lessen I no very little about them nice save.

    • @UncleDoug
      @UncleDoug  5 ปีที่แล้ว

      You're welcome, Ron :)

  • @treadmillrepair754
    @treadmillrepair754 2 ปีที่แล้ว

    Nice job, I love your dog.

    • @UncleDoug
      @UncleDoug  2 ปีที่แล้ว

      Thanks twice, Ricardo :)

  • @paulhammersley4562
    @paulhammersley4562 8 ปีที่แล้ว

    another good one, thank's doug,

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +PAUL HAMMERSLEY You're welcome, Paul :)

  • @michaeljohnaustin6745
    @michaeljohnaustin6745 8 ปีที่แล้ว

    Great video ,

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Michael Austin Thanks, Michael.

  • @theabsolutetruth3364
    @theabsolutetruth3364 6 ปีที่แล้ว

    I bet your fun guy to hang out with ... lol ... I love your sarcasm ... Priceless ... ))) ... Thx for the Knowledge Uncle Doug ... ))) ... Also , Priceless ... ))) ... Blessings to you and your other half ... Say hey to Rusty for me , oh Yea ... Kitty ... )))

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      Thanks, TA. Sarcasm is like aftershave lotion......a little can go a long way :) But when it's directed at objects and deeds, rather than specific individuals, I tend to like it too......as you can probably tell ;) The pets all say "Hi".

  • @lavejim11
    @lavejim11 8 ปีที่แล้ว

    Great video...that amp does look like it might have spent some time in an attic or a barn...good troubleshooting. My regards to Rusty.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Jim Lavespere Thanks, Jim. With so much rust, it must have been in a damp location....yet the wooden cabinet is in great shape. Very mysterious.

  • @denniswalsh8476
    @denniswalsh8476 8 ปีที่แล้ว

    Great surgery on the output transformer and finding the primary coil end (without making the patient any worse). Best ever for me was managing to (accidently?) find, clear and re-insulate a shorted pair of leads on the core of a Twin Reverb II power transformer. Good luck too, an "in kind" rewind by Mercury Magnetics was going to be over $300 (for a $500-600 amp.).

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +dennis walsh Thanks, Dennis, and congratulations on your successful (and money saving) surgery :)

  • @christopherweber8047
    @christopherweber8047 7 ปีที่แล้ว

    I love your videos! They make it very easy to understand how a amp and the components work! At the moment my diy amp (JCA20HV like amp) make a single "knock" when I get over 10 o'clock, 1 o'clock and 4 o'clock with the master volume. When I pull one El84 out, the amp starts with motorboating but only when I set the master exactly at this 3 points... Very strange. Never had a problem like this.

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      Have you checked all your electrolytic caps, including the cathode bypass caps, and your output transformer ??

    • @christopherweber8047
      @christopherweber8047 7 ปีที่แล้ว

      Uncle Doug thanks for answer! :)
      Yes I checked them all twice....all seems to be fine. I cut of the negative feedback; the motorboating is gone now. Maybe I should take a closer look at die PI/whole PA.
      Thanks you
      With best regards from Germany

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      You're welcome, Christopher. Let us know what was causing the problem, once you find out what it was.

    • @christopherweber8047
      @christopherweber8047 7 ปีที่แล้ว

      Sure! I Let you know!
      Thanks

    • @christopherweber8047
      @christopherweber8047 7 ปีที่แล้ว

      Hi,
      I can't find the main issue... I believe there is a much bigger issue in my amp. Do you ever had an issue like, that the plate voltage go down by turning the bias Poti?
      With best regards

  • @tectalabyss
    @tectalabyss 8 ปีที่แล้ว

    Hello Doug. What a wonderful treat, to find another awesome video from you, waiting in my email. :) Though Molly is laying on her back sound asleep She sends her regards to You Rusty and handsome Jack. Has always very well done,in both fun and very Educational . I really hope to see more videos from you.
    All my best.
    Bobby

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +Bobby Tectalabyss Thanks, Bobby, and best regards to Molly :)

  • @hnatyshyn
    @hnatyshyn 2 ปีที่แล้ว

    Hey Uncle Doug. That's a great lesson again.
    A thing that caught my attention is your analog voltmeter because I have the same. It needs a bit of maintenance, but my interrogation was about it's power. I was wondering if there was a way to power it other than with the many batteries. I reckon they are powering different parts of the circuit, but perhaps there is a way to simplify the thing.

    • @UncleDoug
      @UncleDoug  2 ปีที่แล้ว +1

      Thanks, Francois. You could probably wire up a power supply for the Simpson meter......but batteries sure are easier.

  • @raymondsmith6494
    @raymondsmith6494 3 ปีที่แล้ว

    Love this video!!! Class dog.

    • @UncleDoug
      @UncleDoug  3 ปีที่แล้ว +1

      Thanks, Ray :)

  • @tubical71
    @tubical71 8 ปีที่แล้ว

    Nice litte repair video, excellent work, Doug!...thanx for sharing! :)
    Not very uncommon...i seen a lot of amps with open (=got loose somehow) windings, so sad...
    Some people don´t treat their gear well...
    Especially in old radios this open pri winding problem is very common but here mostly from "cooking" the OPT.
    When a coupling cap on the output tube got leaky the bias is usually too hot and this is mostly the reason why the primary coil of the OPT cuts if the radio is on for a longer period. Is it will still work, but not for higher volumes, but at low volumes it is hardly being noticed that there is indeed something wrong with it.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      +TubiCal You're welcome, TC. I don't recall ever having seen (or heard) a guitar amp motorboat like this one. Is it a normal byproduct of an open OPT primary winding ?

    • @tubical71
      @tubical71 8 ปีที่แล้ว

      No in general, but they almost will do any silly thing you can think of.....I even had an amp on my bench which was doing well until its volume had been cranked up to about 70%...the owner said the overall volume was reduced...It was a nearly class A PP 6V6 amp...
      Another one was oscillating when a signal was fed into...another one distorted (that´s what i do expect when having such an issue)
      I found that open (terminal) connections mostly happened in Amp heads. And also these had been seeing a lot of traveling...
      I guess some tranny companies don´t expect huge vibrations...but they do occur....
      The other thing is when Amps have seen vast overload conditions....wrong speaker impedance and/or underrated speakers connected....if a speaker dies it usually have a shorted out voicecoil and smoke the OPT. Or it opens and if it´s the only speaker it takes the OPT with it as well....No load, causes heavy reflected voltage and this causes arcings in the primary...
      I whish the Amp makers would take these conditions into account when they "design" them circuits....But they simply don´t...
      It´s not that hard...a 47Ohms permanent parallel connencted resistor may be 25Watts would help prevent overarcing with no load may in conjunction with a external arcing path/spark gaps (for example, all philips ProAudio Tube Amps during 50s/60s had these builtin)
      Also a snubber network (usually 10Ohms in series with several hundred pico farads) will help to prevent arcing due to no load conditions even with a connected speaker at high frequencies (if it somehow tries to oscillate, or the speakers impedance rises along with higher frequencies)
      And an in series fuse at the speaker terminals 1.5times max. rated output current helps when a short circuit occurs.
      All these "mods" are rather cheap, but helps the OPT to stay save, even at full blast and/or roasted speakers.
      But in order to maximize profit they put cheap and flimsy trannies inside....
      If i take a look in a today´s made "name" tube head and compare it to some made in the 60s/70s the iron is noticeable smaller....ok we have far better metalworks today, and therefore more induction headroom (0.9 to 1.1 Tesla in the old days compared to 1.5 up to 1.8T for today´s made core iron) in it...but if you have an "100Watt" rated today´s amp and its OPT can only deliver around 60Watts when measured until hard cliplling there´s something wrong, It still sounds "loud" but....hmmm...you know....not a good feeling..
      That´s my two cents...;)

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +1

      Thanks, TC. Informative as usual :)

  • @cmguitar50
    @cmguitar50 6 ปีที่แล้ว

    Great repair! I'm trying to track down an intermittent problem on my Pro Reverb - I hate intermittent problems!!

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      Thanks, CM. So do I......they seem to occur when you are least ready to cope with them.

  • @mikedambeck7136
    @mikedambeck7136 8 ปีที่แล้ว

    +10K on the Simpson 260! Great Detective work! That is indeed a very interesting to find.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      Thanks, Mike. Glad you like it :)

    • @mikedambeck7136
      @mikedambeck7136 8 ปีที่แล้ว

      You are welcome good sir. You and Rusty please keep delivering true Craftsmanship.

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว

      We shall, as long as we have encouragement from nice viewers, like you :)

  • @tubehead2002
    @tubehead2002 7 ปีที่แล้ว +1

    Good job.

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      Thanks, TH :)

  • @henryedwards4116
    @henryedwards4116 4 ปีที่แล้ว

    I wish dogs could live forever, R.I.P. Rusty. ( I also love your videos)

    • @UncleDoug
      @UncleDoug  4 ปีที่แล้ว

      Me too, Henry. Thanks :)

  • @robertw1871
    @robertw1871 3 ปีที่แล้ว

    Indeed sir, the low, but still slightly present voltage would seem to indicate a slight charging of a capacitor then breakdown conduction bleeding (in the rectifier) off the charge and repeating... there would be some induction even with the open winding to build up a charge with very limited current capacity since it’s basically functioning as an antenna at that point... nice find and fix...

    • @UncleDoug
      @UncleDoug  3 ปีที่แล้ว

      Thanks, Robert.

  • @peterbustin8604
    @peterbustin8604 6 ปีที่แล้ว

    I love Rusty !!

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      It's hard not to, Peter. He's a very special guy :)